John Stefandis: Trompe l’oeil has always been a favorite. It is lighthearted and gives a dimension to a room or staircase landing.

Geoffrey Bradfield: I find the introduction and use of mirror creates an immediate sense of illusion, adding instant infinity and volume, and a sense of romance.

Q: In a large loft space, what’s the best way to visually divide the room into a series of separate but connected spaces?

Terry Hunziker: Use almost-floor-to-ceiling panels. These could be of different materials from the walls, like steel, wood, plaster or translucent glass. Experiment with a floor pattern that switches materials—from stone to wood, for instance.